<M§ Praporihiu of Carhon in Mineral Coal. 



A Jynopthat ttttvcf fc 'hM diffcretrt S.rU of Miueral Cc. 



100 parts 



Oirbon. 1 Bitomcn. I Afhes. I Specific gravity. 



Malthi 



Afphalt 



Kilkenny 



Compaft cannel 



Slaty cannel 



Whitehaven 



Wigan 



Swanfey 



JLeitrim 



Newcaftle 



8 

 3' 



97.3 

 7S.2 

 47,62 



57 



6",73 

 73.53 

 7 '.43 

 58 



^8 



21,68 maltha 

 32,52 maltha 

 41,3 mixt 

 36,7 mixt 

 23,14 mixt 

 23,37 ""!*' 

 40 mixt 



3i7 

 3.' 



20 



1.7 

 '.57 

 3.33 

 5,20 



2,070 

 1,117 

 ' *,S26 

 1,232 

 1,426 



J.2S7 

 1,268 



J.3 57 

 1,351 

 i>27i 



To thefe rcfults 1 fhall add a few more taken from a Treatlfe on Pit Coal, lately publlllied 

 by Signior Fabroni. The Italian coals wrere examined by himfelf •, the French and German 

 by other chemlfts— All by diftillation. 



100 parts 



Coals of Halles 



of Tudertino 

 of Cortolla 

 of Macinaia 

 Stony of ditto 

 of Mocaio 



Thefe coals contain very little afphalt, but chiefly maltha. 



Moft coals afford a volatile alkali by diftillation :— this feems to me to be rather a produa 

 of the operation arifing from the union of hydrogene and mephitic air, and thus the al- 

 kaline baGs of the ammoniacs found on volcanos feems to have been formed. Coals a!fo 

 afford an acid, commonly the marine, or if pyritous, alfo the vitriolic, more rarely the 

 fuccinous. 



According to Mr. Jars, 100 parts of the beft EngUfli coal give when charred 63 of 

 coakt t ; but Hielm found the refiduum of die beft Englilh coals diftilled, to amount to 

 73 percent, and Dr. Watfon found the refiduum of Newcaftle coal to amount only to 58 

 per cent. Thefe refults neceffarily differ according to the degree of heat applied, the du- 

 ration of the combuftion, and the variable admiffion of air. It is plain the bitumen is 

 never totally expelled, at leaft not until moft of the carbon is confumed ; but much more 

 of it is expelled by combuftion than by diftillation. Watfon, p. 27 and 2« t- 



' Probably 1,07. 



t I Jan«, 319. 



: Tbi( paper it ukcB from the Sec.nd Volume of Elements of Mineralogy, lately publiihcd. 



III. Obfervntknt 



